I'm building a simple breadboard for testing purposes. I'd like to use connectors like the ones in the old Radio Shack Science Fair toys: small circular springs mounted vertically, with some kind of fixation at the bottom so you can fasten it to the board (for instance a horizontal smaller wire loop that you can run a screw through). You insert the wires and component leads in between the turns of the spring.

Trouble is I cannot find the springs. Have spent a couple of hours doing arcane Internet searches both in general and at hardware sites such as McMaster Carr. I have used all sorts of search terms including various combinations of:

The closest I have found are the "extension springs" at McMaster but they won't work because they don't have that loop at the bottom, to fix the spring to the board (they have loops but the loops stick out vertically, rather then being horizontal in line with the axis). I have also found some "close, but no cigar" items from jewelry supply stores (those springs are too small).

Perhaps these little springs have a very specific name? Can anyone help? They are clearly still in production because my local toystore has several "old fashioned" electrical educational toys that make use of them.

Otherwise I may have to find an old Science Fair kit and cannibalize it, but I'd like to avoid that if possible.

Several Radio Shack learning labs over the years have used them. Check with radio shack parts and see if they can be had as replacement parts.

Nowadays it looks like Radio Shack is stocking the Elenco "electronics labs" rather than its own branded stuff. The Elenco "labs" do use the spring clips, in great quantities. So I have emailed Elenco customer service and asked if they could help me out with finding these connectors.

For what it's worth, in its sales materials Elenco describes these items as "spring-coil connectors." Googling that term yields wide availability of these little springs, but they are all designed for jewelry or similary hobby work (basically, for fastening things like leather thongs together). They are too small to serve as connectors for a breadboard, and they lack the little mounting loop at the bottom.

UPDATE: I went through about 50 drawers of parts before finding the springs.

I have 15 of the springs and I also found 10 other devices which is a pin that goes into perfboard holes; are spring loaded. The end or plunger is pushed down and it opens a slot to insert wires or components leads. Release the spring and the wires/leads are held in place.

I have 15 of the springs and I also found 10 other devices which is a pin that goes into perfboard holes; are spring loaded. The end or plunger is pushed down and it opens a slot to insert wires or components leads. Release the spring and the wires/leads are held in place.

If you can use these, let me know.

That's fantastic. I'd only be interested in the first lot (the 15 springs) as this is to complete a really neat "vintage" educational course ("How to Understand and Use Your Vacuum Tube Voltmeter"). I actually only need nine of them. I could have used different connectors but it is rather neat to complete the entire course using entirely the original "equipment."

The breadboard is used to connect various combinations of resistors and capacitors to the VTVM: voltage dividers, RC circuits and so on.

Speaking of VTVMs, mine (Eico 232) had an intermittent fault in its Function switch that was driving me crazy. After months of unsuccessful repair attempts (with Deoxit, or with tentative probing with small screwdrivers, and so on), last weekend I took the plunge and actually disassembled the rotary wafer switch, which involved "breaking" the ends of the side rods on the index assembly (the rods were the "rivet head" type, not the screw type). Sure enough, the contacts turned out to be bent out of position and that was easy to fix. The tricky bit was reassembling the wafers onto the broken rods. I ended up securing the wafers back onto the rods with Superglue and it is working fine. Phew. I love building/restoring stuff but vintage rotary switches are a pain! In my experience so far, they account for a large proportion of the failures in old equipment, and because the wafers are often heavily customized, they can be very hard or impossible to replace with equivalent new/NOS parts. The old phenolic material can be very fragile and shatter under even mild stress, such as de-soldering a component.

The email address is current and my mailing address is as listed in the profile.

Just hit the right arrow to scroll through the pictures. I found an old Heath EF-1 "How to Understand and Use Your VTVM," disassembled it, cleaned up the chassis and parts ... and put it back together. Now, time to do the educational "experiments" in the manual.

I reallly like breadboard projects made with Fahnestock clips. My son and I made breadboard crystal radio set using the Fahnestock clips - the work really well and gave the project the right look. Check out an article I wrote for my website for a picture and info on the clip and our project.

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